Mouse doody

From: Claude Ceccon <>
Date: Wed Jan 14 11:29:48 2004

Some comments on cleaning electronics which have been despoiled by
biorchid rodents and other sources:

Loose stuff should be removed by dusting, vacuuming or blowing off the
offending offal. However, in low humidity locations be aware that you
can build up fairly large static charges can be generated by vacuum
cleaners / air jets. I normally place boards on conductive mats and
ground the nozzle to the mat, or in the case of cabinets, the cabinet.

The remaining junk to be removed is either water soluble or not. If
water soluble, water is the best means of cleaning. If insoluble, then
a suitable surfactant added to water will remove oils, etc. That leaves
the nasty stuff that requires a solvent. Isopropyl alcohol is a good
starting choice - anything stronger is likely to dissolve wanted items.

If you use soap do not use one that is extremely caustic - you can
remove things that you want like the copper runs. Hand dishwashing
soaps are generally safe.

However, the last step in any cleaning process should be a rinse with
** de-ionized ** water and a thorough drying. This will remove any
conductive remnants that remain. I generally air dry my stuff over
night (Arizona, but recommend 6 months for Florida). If you are in a
hurry, a hair dryer or and oven at 140F/60C will hasten things ( using
heat guns and warmer ovens runs the risk of doing in capacitors and
removing surface mount items). Distilled water can be used in a pinch,
but be aware that the stuff is corrosive. This last step is especially
important if you have CMOS or analog circuits involved. The military
uses pure alcohol as a final step to remove any remaining water.
However, the stuff they use is far less volatile than isopropyl and
does not contain any water.

Of late I have been playing with a daily shower cleaner (USA->TILEX
Fresh Shower). The stuff has isopropanol, a great surfactant, and a
chelating agent. The latter ingredient will take off those insoluble
minerals that remain. Seems to work well. If you go this route, ensure
that you read the label - there are shower cleaners that have acid in
them and will definitely take everything off the board... Still do the
de-ionized rinse afterwards.

A couple of precautions: dip switches should be sealed with tape to
limit wetting. I generally drop some switch lubricant/cleaner in each
and exercise the switch subsequent to cleaning. Unplug and remove
relays, if possible. Switches, relays, connectors, and edge connectors
should get a treatment with a suitable lubricant/preservative.

Lastly, you should do all the above in the undisturbed privacy of your
home. A number of years ago, a friend's salt sculpture atop his TV
broke filling the set with the super-saturated salt solution. I told
him to take the set out back, remove the back, and hose it out. A nosy
neighbor asked what he was doing and he said that he was watering the
set to make it grow bigger. He related the line to the sheriff that
subsequently showed up. I then spent the afternoon convincing the
psychologist that hosing down a TV was a rational act...

        Claude Ceccon
Received on Wed Jan 14 2004 - 11:29:48 GMT

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